Back-up pad and abrasive sheet



July 11, 1961 R. .1. WALTERS BACK-UP PAD AND ABRASIVE SHEET Filed Aug.7, 1959 B ..IO 5 E w A is? INVENTOR. ROY J. WALTERS BY W MW Unite Thisinvention relates in general to a device for finishing or working thesurfaces of materials, and more particularly to an abrading device, andstill more particularly to a combination back-up pad and detachableabrasive sheet.

Heretofore, abrasive sheets which were detachable from a holder had onemain disadvantage in that too much time was consumed in effectingreplacement of abrasive sheets.

Accordingly, it is an object of the present invention to provide animproved detachable abrasive sheet that may be quickly and easilyreplaced without the use of special tools.

Another object of this invention is in the provision of a combinationback-up pad and abrasive sheet adapted to be mounted on a holder,wherein the abrasive sheet may be easily applied and locked to theback-up pad, and easily removed therefrom.

Still another object of this invention resides in the provision of acombination back-up pad and abrasive sheet including a snap fastenerhaving male and female parts, wherein one of the parts is secured to theabrasive sheet and the other part is secured to the back-up pad, therebypermitting easy mounting and dismounting of the abrasive sheet on theback-up pad.

A further object of this invention is in the provision of a combinationback-up pad and abrasive sheet including a snap fastener having male andfemale parts, wherein one of the parts is secured to the abrasive sheetand the other part is secured to the back-up pad, and means is providedon the back-up pad for engagement with the abutting surface of theabrasive sheet to prevent relative movement between the abrasive sheetand back-up pad.

A still further object of this invention is to provide a combinationdisc-shaped back-up pad and abrasive disc having means for permittingeasy application of the abrasive disc to the back-up pad and assuringpositive centering and locking action, wherein no protrusions will existon the abrasive side of the disc.

A further object of this invention is in the provision of a combinationabrasive disc and disc-shaped resilient back-up pad including a snapfastener having coacting male and female parts, wherein one of the partsis secured to the non-abrasive side of the abrasive disc and the otherpart is recessed from the outer surface of the back-up pad, and a layerof tacky substance is provided on the outer face of the back-up pad forengagement with the non-abrasive side of the abrasive disc to preventrelative movement between the abrasive disc and back-up pad.

A still further object of this invention is to provide a combinationabrasive sheet and back-up pad including a plurality of snap fastenersfor detachably securing the abrasive sheet to the back-up pad, wherebyeasy mounting and dismounting of the abrasive sheet on the back-up padis obtained without the use of any special tools.

Other objects, features, and advantages of the invention will beapparent from the following detailed disclosure, taken in conjunctionwith the accompanying sheet of drawings, wherein like reference numeralsrefer to like parts, in which:

FIG. 1 is a perspective view of the invention illustrating the abrasivesheet removed from the back-up pad, and the back-up pad is mounted on aholder;

FIG. 2 is an axial sectional view taken through the em- Sates Patent fbodiment of FIG. 1 and illustrating the abrasive sheet in r 2,991,596Patented July 11, 1961 removed position in solid lines and in mountedposition in dotted lines;

FIG. 3 is a view similar to FIG. 2, and illustrating the reversal ofpositioning of snap fastener parts wherein the female part is secured tothe abrasive sheet and the male part is secured to tthe back-up pad; and

FIG. 4 is a perspective view of an orbital sander and illustrating theapplication of the present invention thereto.

Referring now to the drawings, and particularly to FIGS. 1 and 2, thepresent invention includes generally a resilient back-up pad 10 and anabrasive sheet 11. In this embodiment, the back-up pad and abrasivesheet are disc-shaped, and the back-up pad is constructed to be mountedon a rotatively driven holder or mandrel, generally designated by thenumeral 12.

The holder 12 includes a head 13 and a spindle 14, wherein the spindleis adapted to be connected to a rotative source of power, and the headis adapted to have the back-up pad 10 attached thereto. The head 13 alsoincludes a diametrically reduced portion 15 having an inwardly spacedannular groove 16 defining an annular retaining flange 17 spacedoutwardly from a backing surface 18 on the head.

The back-up pad 10 is preferably made of rubber, but may be made of anyresilient material, and includes an annular enlarged portion 19 havingan inwardly projecting radial lip 20 for engagement over the flange 17of the holder head 13 by being received in the annular groove 16thereof. Thus, the back-up pad 10 may be removed from the holder 12 ormounted thereon by means of manipulating the back-up lip 20 relative tothe holder flange 17.

As seen most clearly in FIG. 2, the abrasive disc 11 includes a sheet ofmaterial 21 having abrasive particles 22 secured to the outer side and asmooth surface 23 on the inner side. The sheet of material 21 and thetype of abrasive material 22 secured thereon may be of any known typesuitable to the Particular type of operation of the user. For example,the sheet of material may be paper, plastic, fabric, steel, or any othersuitable material.

In order to detachably mount the abrasive disc 11 to the back-up pad 10,a snap fastener including a male part '24 secured to the smooth side 23of the abrasive disc 11 and a female part 25 secured to the back-up pad10 may be provided. The male part 24 may be secured to the abrasive disc11 if the disc is steel by welding or soldering, or if the disc is ofpaper or other stock by a suitable adhesive. Likewise, the female part25 may be secured to the resilient back-up pad 10 in any suitablemanner. Depending on the type of use required for the abrasive sheet andback-up pad, the snap fastener may be constructed of steel, rubber,plastic, or any other suitable material.

As noted in FIG. 2, the female part 22 of the snap fastener is recessedfrom the outer surface of the back-up pad 10, and a centrally slightlydish-shaped portion 26 is provided in the outer surface of the back-uppad, whereby attachment of the male part 24 to the female part 25assures the absence of protrusions from the outer abrasive side of thedisc 11.

In order to prevent relative movement between the abrasive disc 11 andthe back-up pad 10, or relative rotation between these parts, a layer oftacky or adhesive material 27 is provided on the outer surface of thebackup pad 10 for engagement with the smooth surface 23 of the abrasivedisc 11. Inasmuch as the snap fastener parts are centrally mounted onthe back-up pad and abrasive disc, positive centering and locking actionof the abrasive disc tothe back-up pad is accomplished, and it will bereadily appreciated that replacement of the abrasive disc can beaccomplished with ease.

The embodiment of FIG. 3 differs from the embodiment of FIGS. 1 and 2only in that the male and female parts of the snap fastener are reversedin position, Wherein the male part 28 issecured to the back-up pad 10,and the female part 29 is secured to the smooth side 23 of the abrasivedisc 11.

The combination abrasive sheet and back-up pad unit of the presentinvention may also be utilized in connection with orbital sanders, andan orbital sander 30 is illustrated in FIG. 4.

The orbital sander 30 includes a main housing 31 having a handle 32attached thereto, and a driving plate 33. Suitably secured to thedriving plate 33 is a rubber backup pad 34, like the back-up pad of theother embodiments except rectangular in shape. A layer of tackysubstance 35 is provided on the outer surface of the backup pad 34, andfemale parts 36 of snap fasteners are secured in recessed fashion at thefour corners of the backup pad. In this instance, the abrasive sheet 37is rectangular in shape, but may be constructed of the same materials asthe abrasive disc 11 of FIGS. 1 to 3. A plurality of male parts 38 aresuitably fastened to the smooth side of the abrasive sheet 37 and inalignment with the female fasteners 36 on the back-up pad 34, wherebysnapping of each male part 38 into its corresponding female part 36 willattach the abrasive sheet 37 to the back-up pad of the orbital sander.The tacky substance 35 will engage the smooth surface of the abrasivesheet 37 and inhibit relative movement between the abrasive sheet andback-up pad. As in the embodiments of FIGS. 1 to 3, the abrasive sheet37 may also be easily removed and replaced with a new sheet by simplyunsnapping the male parts from the female pants.

It will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention, but it is understood that this application is to be limitedonly by the scope of the appended claims.

The invention is claimed as follows:

1. The combination of a resilient back-up pad and an abrasive disc, saiddisc including a sheet of material having abrasive particles secured toone side thereof and being smooth on the other side, a snap fastenerhaving coacting male and female parts for detachably mounting said discon said back-up pad, one part of said fastener being secured to saidsmooth side of said disc and said other part of said fastener beingsecured to said back-up pad, and means on said back-up pad for engagingsaid smooth side of said disc and preventing relative movement betweensaid disc and back-up pad.

2. The combination of a resilient back-up pad and a sheet of abrasivematerial having abrasive particles secured to one side thereof and theother side thereof being smooth, a snap fastener having coacting maleand female parts for detachably mounting said sheet on said back-up pad,one part of said fastener being secured to said smooth side of saidsheet and said other part being secured to said back-up pad, and meanson said back-up pad for engaging said smooth side of said sheet andpreventing relative movement between said sheet and back-up pad.

3. The combination of a resilient back-up pad and a sheet of abrasivematerial having abrasive particles secured to one side thereof and theother side thereof being smooth, at least one snap fastener havingcoacting male and female parts for detachably mounting said sheet onsaid back-up pad, one part of said fastener being secured to said smoothside of said sheet and said other part being secured to said back-uppad, said part secured to said back-up pad being recessed from the outersurface thereof, and means on said back-up pad for engaging said smoothside of said sheet and preventing relative movement between said sheetand back-up pad.

4. The combination of a resilient back-up pad and a sheet of abrasivematerial having abrasive particle secured to one side thereof and theother side thereof being smooth, at least one snap fastener havingcoacting male and female parts for detachably mounting said sheet onsaid back-up pad, one part of said fastener being secured to said smoothside of said sheet and said other part being secured to said back-uppad, said part secured to said back-up pad being recessed from the outersurface thereof, and a layer of tacky material on said backup pad forengaging said smooth side of said sheet and preventing relative movementbetween said sheet and back-up pad.

5. The combination of a resilient back-up pad and an abrasive disc, saiddisc including a sheet of material hav ing abrasive particles secured toone side thereof and be :ing smooth on the other side, a snap fastenerhaving coacting male and fem-ale parts for detachably mounting said discon said back-up pad, one part of said fastener being secured centrallyof said smooth side of said disc and said other part being securedcentrally of said backup pad, and means on said back-up pad for engagingsaid smooth side of said disc and preventing relative movement betweensaid disc and back-up pad.

6. The combination of a resilient back-up pad and an abrasive disc, saiddisc including a sheet of material having abrasive particles secured toone side thereof and being smooth on the other side, a snap fastenerhaving coacting male and female parts for detachably mounting said discon said back-up pad, one part of said fastener being secured centrallyof said smooth side of said disc and said other part being securedcentrally of said backup pad, said part secured to said back-up padbeing recessed from the outer surface thereof, and means on said back-uppad for engaging said smooth side of said disc and preventing relativemovement between said disc and back-up pad.

7. The combination of a resilient back-up pad and an abrasive disc, saiddisc including a sheet of material having abrasive particles secured toone side thereof and being smooth on the other side, a snap fastenerhaving coacting male and female parts for detachably mounting said discon said back-up pad, one part of said fastener being secured centrallyof said smooth side of said disc and said other part being securedcentrally of said backup pad, said part secured to said back-up padbeing recessed from the outer surface thereof, and a layer of tackymaterial on said back-up pad for engaging said smooth side of said sheetand preventing relative movement between said sheet and back-up pad.

8. The combination of a resilient back-up pad and a sheet of abrasivematerial having abrasive particles secured to one side thereof and theother side thereof being smooth, a plurality of snap fasteners havingcoacting male and female parts for detachably mounting said sheet onsaid back-up pad, one part of each fastener being secured to said smoothside of said sheet and said other parts being secured to said back-uppad, and means on said back-up pad for engaging said smooth side of saidsheet and preventing relative movement between said sheet and back-uppad.

9. The combination of a resilient back-up pad and a sheet of abrasivematerial having abrasive particles secured to one side thereof and theother side thereof being smooth, a plurality of snap fasteners havingcoacting male and female parts for detachably mounting said sheet onsaid back-up pad, one part of each fastener being secured to said smoothside of said sheet and said other parts being secured to said back-uppad, and a layer of tacky material on said back-up pad for engaging saidsmooth side of said sheet and preventing relative movement be tween saidsheet and back-up pad.

10. The combination of a resilient back-up pad and a sheet of abrasivematerial having abrasive particles secured to one side thereof and theother side thereof being smooth, a plurality of snap fasteners havingcoacting male and female parts for detachably mounting said sheet onsaid back-up pad, one part of each fastener being secured to said smoothside of said sheet and said other parts being secured to said back-uppad, said parts being secured to said back-up pad being recessed fromthe outer surface thereof, and a layer of tacky material on said back-uppad for engaging said smooth side of said sheet and preventing relativemovement between said sheet and backup pad.

References Cited in the file of this patent UNITED STATES PATENTS2,227,707 Cooper Jan. 7, 1941 6 Hey Nov. 14, Crosby Mar. 20, BurleighMar. 20, ONeil July 7, Tocci-Guilbert Jan. 19, Peterson Mar. 20, ShortJuly 30, Carr Jan. 28, Kohlwey Mar. 17,

